REMOVAL OF CYANOBACTERIA VIA NATURAL ZEOLITE

摘要

The invention relates to the removal of cyanobacteria from water via natural zeolite which is rich in HEU-type zeolite (Heulandite-Clinoptilolite). The HEU-type zeolite is found mainly inside the characteristic shards and is surrounded by a very thin zone of argilleaceous minerals. The mixing ratio of the natural zeolite and the stirring time thereof varies and depends on the zeolite granularityas well as on the abundance and species of the existing cyanobacteria. The mixing of the natural zeolite lasts for a time interval allowing the full performance of the adsorption, absorption and surface deposition process of the cyanobacteria in the micro-pores, medium-pores and macro-pores of the natural zeolite what leads to the retention of the cyanobacteria and the subsequent sedimentation thereof in the form of odourless and cohesive zeo-sludge which is composed of the natural zeolite and the retained therein cyanobacteria. The overlying clear water is free from cyanobacteria or contains-in comparison to their initial abundance- more lesser cyanobacteria; full retention of all or almost all cyanobacteria contained in the initial water sample can be achieved by second or third treatment of water with natural zeolite. The best final result has been observed after use of natural zeolite of less than 0,5 mm granularity, where the most of the natural zeolite shards have been fragmented and have activated the Bronsted surface acid positions and the Lewis base positions of the HEU-type zeolite, respectively.